Disk harrow



Jan. 11, 1944. Q w ni 2,338,698

DISK HARROW Filed July 12, 1940 2 Sheets-Sheet 2 INVEN TOR CHARLES HPatented Jan. 11,

UNITED STATES PATENT OFF zssaoas a msx minnow Charles H. White, Moline,111., assignor to Deere nois & Company, Moiine, 111;, a corporation ofIili- Application July 1 2'. 1940, Serial No. 345,020 50 Claims. (01.55-41) This invention relates to agricultural implements and moreparticularly to implements such as disk harrows and'the like that areadapted to be drawn by a tractor. 1

The object and general nature of this invention is the provision ofimproved means, utilizing stored energy or deriving energy from thetractor,-.

ried by its own momentum, wherethe spring means is more ,or less slack,whereby upon proper manipulation of the controls, the movement of thegangs toward their angled position is sufllcient to overcome the initialforce of such spring,

' whereupon the completion of the movement of actuating the draftconnections between the disk harrow and the tractor so that thei'fi'rrowmay be angled or straightened during the forward travel of the machineat its normal rate. Another feature ofthis invention is the provision ofmeans energized to shift the hitch into a position such that the gangscan be swung into an angled position after having been shifted into astraightened position by the draft force. this being accomplishedwithout backing the tractor and, as a matter of fact; withoutinterrupting the forward travel of the outfit at its normalpace. Y

Another feature of the present invention is the provision of means fordetermining the angled back into their or operating position of thegangs, the setting of g which isnot disturbed by movement of the gangsinto their straightened or non-operating, position. Still further, it is'a feature of this invention to provide a disk harrow controlledbyvmeans deriving power from the tractor, which isso arranged thatthegangs may be shifted into their non-working position without losing thesetting of the angled or working position.

It is a further feature of this invention to provide hydraulicmechanism, deriving power from the tractor, for controlling theretractable. drawbar and the gangs.

larly, it is a feature of this invention to provide such spring means soconstructed and arranged that when tensioned it is capable of exertingsufficient force to impart momentum to the harrow to cause the same tobe carried forwardly, relative to the tractor, into a position where theforward draft may be utilized to angle the gangs, yet in such position,to which the harrow is carthe accompanying drawings gjthe gangsintotheir angled position places the proper amount of tension in the spring.

These and other objects and advantages of the present invention will be.apparent to those skilled in the art after a consideration of thefollowing detailed description taken in conjunction with In thedrawings:

Figure lisafragmentary plan view of a disk harrow in which theprinciples of the present in- I venticn have been incorporated, theharrow being shownin angled working position:

Figure 2 is a view similar to Figure 1 but showing the position of theparts after the front latch has been released to permit the gangs toswing tiom . e Figure 3 is a view similar to Figure 2, showing theposition of the parts after the rear latch has been released to permitthe power stored in the spring to retract, or cook, the slidable drawbarmember relative to the companion drawbar member; I v

Figure 4 is a longitudinal sectional viewitaken at an enlarged scalegenerally along. the line H of Figure l;

. Figure 5 is a fragmentary view of a modified formof the presentinvention wherein hydraulic means is' utilized for cooking the harrowdrawbar I and straightening the gangs,- said hydraulic means derivingpower from'the tractor:

Figure 6 is a fragmentary side view of the tractor and harrow providedwith the shown in Figure 5; and

Figure 7 is a schematic view of one form of controlling valve mechanismwith which the hydraulic unit of Figure 5 is adapted to operate.

Referring now to Figures 1 to 4, involving the feature of storing a partof the power as developed hydraulic unit by the tractor or otherpropelling means, it will be seen that the disk harrow, shownfragmentarily in the accompanying drawings, includes a frame I, a pairof front gangs 2 pivotaily connected to the frame I, and a pair of reargangs (not shown) also pivoted at their inner ends to'the frame i andoperatively connected through linkage l with the front gangs, this beingthe construction disclosed generally in my prior United States PatentNo. 2,264,783, issued December 2, 1941. The frame I straightened ortransport posiincludes a forward extension 8, arms I of which turndownwardly to serve as the pivots for the inner bearings 4 of the frontgangs. The harrow also includes suitable means, such as springs I,

for holding the front and rear gangs against upii thrust, due to thefact that the center of soil resistance against the disks lies below thebearings to which the gang frames are connected.

The drawbar unit of the harrow is indicated in its entirety by thereference numeral i5 and comprises a slidable drawbar proper, preferablyin the form of a channel It having its flanges extending downwardly andwith its web provided with a number of slots l1, and a companion drawbarmember or frame means It, preferably in the form of a pair of angles itconnected together in spaced apart relation by a pair of upper and lowerplates 2| welded or otherwise secured to the forward ends of the anglesl0 and a rear U-shaped bracket, welded to the rear ends of the angles itand apertured to receive a hitch or pivot pin 24 by which the rear endof the drawbar II is pivoted to the front end of the harrow frame I,

both for lateral and vertical swinging movement,

as disclosed in my prior patent mentioned above. 25

.through draft, links to be described later with the so back into theirstraightened position, the slide moving backwardly along the drawbarchanneldisk gangs to shift or swing them between straightened and angledor working positions. A

pair of upper and lower guideplates, indicated -at 20 and 21, aresecured by a bolt 20 to the rear end of the drawbar channel lland serveas stops limiting the outward movement of the channel it by virtue oftheir-engagement with the rear edges, of the front plates 21. Therearward movement of the channel It relative to the. rear drawbar memberII is limited by theengagement of these plates 20 and 21withthe'U-shaped'membar 22, as best shown in Figure 3. At. its forwardend the j channel ll carries an-adiustable angle-limitin plate 20 whichis secured by a bolt 23 in anyone freely movable along the drawbarchannel it and arranged to support a pair of pivots .14 to which thefront ends-of a pair of draftlinkall are coni nected.- The rear ends ofthe links 34 have hook latch 40 except that the lower end of the dog 44ais not beveled. Hence the latch 40a does not ratchet, and when engagedwith the channel I can hold the latter against movement in eitherdirection.

By virtue of the drawbar construction so far described, it will be seen,particularly from Figure 1, that when the slide 30 is latched to thedrawbar channel it, normally the draft pull extends the channel itrelative to the drawbar member II, the plates 26 and 2'I limiting theforward movement of the channel I. relative to the memher It. Since theslide SI is latched to the channel it, this forward movement of thelatter exerts a pull through the draft links 34 and swings the frontgangs into their angled position, the rear gangs (not shown) swingingrearwardly into their angled position by virtue of the interconnectinglinkage 4. The forward end of the drawbar channel I8 is slotted, as at48, to receive a clevis 4!, by which the harrow may be hitched to atractor T, represented by the tractor drawbar it. A cable 8| extendsfrom the latch lever 4| and enables the operator to engage or releasethe latch while sitting or standing on the tractor.

With the parts in operation and in the relative positions shown inFigure 1, when the operator exerts a pull on the cable BI and releasesthe latch mechanism 40, the draft or soil resistance which the disksencounter causes the gangs to swing ll (Figure 2) until the plates IIand 82 (Figure 4) engage the front'edges of the upper and lower plates2| at the front ends of the angles II. This defines the straightened ortransport position of ent inventionto provide power means, deriving itsoperating energy from the tractor or other propelling means,whereby thegangs may be angled or straightened at will, without requiring thatthetractor be backed or otherwise moved in any dl-" The 'U-shaped yoke 22at the rear end of the drawbar is apertured, as at ii, to receive, abolt 82 or other connecting member by which the rear end of a spring 43is connected to the part, 22;

and hence to the frame i of the disk barrow. I The spring 63 extendsforwardly between the two," 1

drawbar angles II and also forwardly within the sliding drawbar channelit, asbest shown in Figure 4. The front end of the spring is securedportions 3! which engage with the forward looped' Mt-in any suitablemanner to a nut member 64 which parts-3 of the forward front gangbearing standards 31, which are connected with the outer bear ings ll ofthe front gangs. The front slide 30 carrice-latch mechanism 40 whichincludes a latch The lower end of the dog 44 is beveled off, asst 4, sothat the drawbar channel I may move rearwardly, relative to the slide30, but the latter is 7 prevented from moving rearwardlyrelativeMythschannel it unless the latch 40 is released; as 'by' swinging thelever 4i forwardly. A similar latch 40a is carried on the plate 2| atthe front-end of is 1 provided with a screw-threaded bore to receive thethreaded end of an adjusting bolt 0!, the forward end of the latterbeing anchored to a lug 00 or other suitable means formed on or carriedby the drawbar channel l4 adjacent its forward end. The adjusting member68 is of sufllcient length to provide for adjusting the tension of thespring 6! to meet various operatingconditions., v The operation of theform-pf the invention described above is substantially as follows:Figure 3 represents v=the drawbar and the assoclatedportions of-theharrow in transport position and with the drawbar slide channel II Vdrawbar section II, and the engagement of the the drawbar memberllandisconstructed like the plates 3i and 32 of the front slide 30against tended position.

which the gangs are in assaeoa the forward'edges of the plates 2! at thefront back against the forward edges of the drawbar end of the drawbarmember ll prevents the disk gangs from swinging rearwardly out of theirstraightenedor transport position. With the parts arranged in thismanner, the tractor i8 may be driven to any point desired and the diskgangs will roll in their straightened position. as is customary whentransporting a disk harrow.

when it is desired to angle the gangs, that is, to swing them into theirangled or working position the rear latch'lla is released, Whereupon'the forward draft pull extends the slidable drawbar ll forwardly untilthe plates 28 and 21 engage the rear edges derstood that the latch lllis'not released but is left engaged.

This extension of the member l8 relative to the I drawbar member I! doestwo things: first, since the slide II is left latched to the slidabledrawbar section ll, the forward draft'pulls the outer ends of the frontgangs into their angled position, as shown in Figure l, or in otherwords,

the resistance of the soil acting against the inner ends of the frontgangs swings them rearwardly into the angled position (Figure l)- whilethe forward draft pulls the outer ends in the direc tion of travelduring the continued movement of the tractor. Figure 1 shows the gangsin their maximum angled position, but if it is desired to operate withthe gangs at a'smaller angle, the

' latch 40 is momentarily released to permit the slide 30 to -drop backa few notches, and then thelatch 4. is reengaged in one of the notchesll of the slidabie drawbar II.

The second result of extending the drawbar section II forwardly is toplace the spring 53 ina-bias ed'or tensioncd condition. The spring l3isso' arranged that in its unstressed condition, that is, when theslidable drawbar section I! is in its rearward position, the spring 63is practically unstressed, and hence there is no substantial resistanceinitially to the extension of the drawbar l6. This permits the diskgangs to swing backwardly, whereupon the disks, being in an angledposition although not at, a great angle, bite into the soil, so that theresistance to their forward travel is materially increased.

' This additional resistance then becomes available as the tractorcontinues to move forwardly to stretch the spring 03, and as will beobvious, I the greater the angle of the disk gangs the greater will bethe draft forces available to stretch the spring, and hence storeenergytherein. when the'parts' reach the position'shown in Figure 1,

with the drawbar slide I. in its maximum ex-,

the latch a is permitted to "-reengage'the slidable drawbar section I,the do .44 of the latch a moving into a rear notch, indicated at Us inFigure 4. Thus, when the latch a engages the slidable drawbar sectionlatched in its biased or stressed position.

. When the farmer reaches the end of the field or otherwise desires tostraighten the gangs when the harrow parts are in the relative positionsshown in Figure 1, all he has to do is to pull on the cable II of thefront latch 40. This will wardly along the rear end of the drawbarsection I! back to the position shown in Figure 2, in

ened position, the slide, plates 3i and 32 being of the plates 11, itbeing un- '00 it when the latter is extended, the spring" is theiraligned or straight- 1 (Figures 2 and 4) instead of being retracted(Figf ure 3). The farmer may then move the harrow to another point bymerely continuing the forl0 ward travel of the tractor, and then whenthe farmer reaches the plac'elwhere he again desires to place the harrowin operating position, all he has to do is to pull the rear cable Ila todisengage the rear latch "a, pulling the dog H of the rear latch out ofthe notch l'la, whereupon the force stored in the stressed spring 63 isimmediately made'available to roll the harrow forwardly. causing thesame to advance relative to the tra'ctor and the drawbar section It. Thespring is 20 constructed andarranged "so that when in its stressedposition it is capable, when released, to

1 roll the harrowforwardly with suiilcient speed not only to overtakethe tractor but also to have sumcient momentum to, carry. the harrowfor- 25, wardly until the plates H at the front end of the drawbarsection II engage the rear edges of the slide plates 3i and 32.1 Thenthe operator releases his pull on the cable- 5i and permits the dog llw, to engage-one of the notches H. In this position 3i) the spring .3 isnot stretched or biased, and hence the latter portion of the forwardmovement of the harrow into the position shown in Figure 3 is due to themomentum originally imparted to the harrow by the force stored in thespring when obit is in its stressed or biased position (Figures 1, 2 and4). In the transport position with the gangs in their straightened oraligned positions, the resistance to the forward rolling of the harrowis quite small and hence no great amount of 40 momentum is required tocarry the harrow forwardly into the position shown in Figure 3 from theposition shown in Figure 2. The mobile stop 20 limits the retractingmovement of the channel i6, "and hence may beset to secure the desiredangle setting, without requiring that the slide ll ,be reset each timethe harrow is angled out of straightenedlposition. After restoring thehar- .I'OW to the position shown in Figure'3, it may then beaplaced inworking or angled position merely by pulling on the rear latch cable 51aand releasing the rear dog a from the notch ll of *thetdrawbar sectionit, "whereupon the inner .ends ofthe gangs will swing back to theposition shown in Figure l, as described above, again placing the spring.3 in its stretched position.

. The present inventionalso contemplates the provision of another formof power means', also deriving power from the tractor, for cooking theslidable drawbar section and. in addition, also available to actuallyforce the harrow into a straightened position, rather than requiringthat Y the harrow be straightened by draft before cocking the slidabledrawbar section, preparatory to subsequently angling-the harrow bydraft.- In in this form of the invention a hydraulic ram unit. includinga cylinder and piston or plunger which able source of fluid pressure onthe tractor, such as an 'oil pump or the like, and is connected betweenthe two relatively slidable parts of a drawbar construction which issubstantially identical with the drawbar construction I! describedabove, except that the spring 63 and associated parts are omitted.Therefore, the drawbar parts that 75 are identical with those describedabove. will for replaces the spring CI, is connected with a suitthe sakeof brevity be indicated by the same ref erence numerals employed above.

The rear, or relatively stationary part I8 of the drawbar I5 is, in theconstruction shown in Figure 5, arranged substantially as describedabove, except that, if necessary, the angles I8 may be extendedrearwardly, as at Illa, to provide proper clearance for the powerangling unit. The power angling unit 98 includes a hydraulic cylinder Ihaving a pair of ears IOI which are secured, as by screws I02, to theplate M. The rear end of the cylinder I00 is open and slidably receivesa piston I05, the forward end of which is provided with suitable sealingmeans I06, such as a leather cup fastened to the piston I in the usualway. The unit 09 therefore constitutes a single action ram unit. Therear end of the piston I05 is recessed, as at I01, and pivotallyreceives the forward end of a piston rod I 08, the

latter being swlngably mounted for limited movement on a pivot pin I09carried by the rear end of the piston I05. The piston rod I08 extendsrearwardly and is provided with a reduced end Il8 which seats in the"upturned end IIO of a bracket III that is slidable on a cross plate H2fixed to the angles I8 in any suitable way, as by ticular details per seof the valve mechanism excent in so far as they cooperate with my gangcontrolling and angling means.

Referring now more particularly to Figure 6, it will be seen that thetractor T to which the harrow H is hitchedis of more or less'conventional construction, embodying a frame I28, front wheel (notshown), and rear wheels I28.

, The self-releasing valve mechanism is indicated welding or the like.The forward end of the bracket I I I is fastened to the rear end of theslidable drawbar I8 in any suitable manner, as by being secured betweenthe plates 28 and 21:: by the bolt 28a (Figure 5), or any other suitablemeans as desired. A nut II8 fixes the rear end of the piston rod I08 tothe bracket III.

Whenever fluid under pressure is introduced into the cylinder I00, thepressure against the inner end of the piston I05 causes the piston I05and piston rod I08 to be forced rearwardly into the position shown inFigure 5, thereby shifting the drawbar channel I8 into its rearmost orref tracted position. If at this time the yoke 88 is latched to theforward portion of the drawbar channel I8 (as shown in Figure 5), thenthe pres sure against the piston I08 will be efl'ective to force thegangs into their straightened position, by virtue of the fact that theyoke 80 is moved rearwardly and hence can exert a rearward pressurethrough the draft links 88 against the outer ends of the gangs.

It will be remembered'that the yoke 80 may be in its full angledposition, in which case the cylinder and piston will be fully extendedby the time the gangs are forced into their straightened position andthe rear edges of the yoke plates 8i and 32 engage the forward edges ofthe drawbar plates 2I. However, to effectively use this form of powerangling apparatus, provision must be made to accommodate forcing thegangs into their straightened position even though the yoke 80 shouldnot be in its iorwardmost position along the drawbar channel I0, as whenthe latch 80 is engaged with one of the intermediate slots I! for thepurpose of holding the gangs in their j suitable manner. I

tended to the power unit 88 and is fixed to ainto the forward end of.

working position but not angled to the maximum extent. To this end, Ihave designed the hydraulic power unit 99 for use with a source ofpressure on the tractor controlled by a self-releasing valve mechanism,whereby when the yoke 80 has been moved up against the forward end inits entirety by the reference character V and includes a valve body orvalve casing I having an extension I3I which is adapted to be bolted tothe housing of the governor G and which is adapted to enclose a pair ofpump gears I I driven in any suitable manner from the governor shaft.Figure 7 'shows the details of the valve mechanism schematically, andfrom this figure it will be seen that the casing I80 forms or isprovided with a chamber I88 which serves as a sump from which 011 orother fluid passes to the pump gears I35. The latter deliver oil underpressure into a high pressure duct I88 which extends to and intersects avertical bore or valve chamber I. or bore I8I communicates with apassage I82: At its lower end the bore I8I opens into a check valvechamber I88, there being a check valve seat I88 at this point. The

lower end of the check valve chamber I88 receive 'a connector I85 end ofa flexible tube The flexible tube I88 is'exconnector I81 threaded thecylinder I00.

The check valve in the chamber I88 is indl cated by the referencenumeral I50 and is of the poppet type. The valve I50 is adapted to closeupwardly against the valve seat I88 for closing oil. communicationbetween the power unit 88 and the passage I39 and I. The valve I58 isprovided with an upper stem I5I which is adapted to be engaged by thelower end of a manually controlled valve, indicated in its entirety bythe reference numeral I58, which is slidable in the bore or passage MI.The lower or inner end of the manually controlled valve I58 is arrangedto abut the upper or inner end of the course, move stem III, but thevalve I58 may, of upwardly relative to the check valve I50 and thelatter may move downwardly relative to the manually controlled valveI58, there being three possible positions of the valve I58, as indicatedin Figure 7 at a, b and c. a

When the valve I58 is in the position shown at a fluid delivered by thepump I85 passes through the passage I88 and into the lower portion ofthe valve chamber I H. The fluid is prevented from passing upwardly pastthe valve I58 and therefore passes downwardly, opening the check valveI50 and passing to the cylinder I00, thereby extending the piston rodI08 and straightening the gangs, provided of course that the yoke 80(Figure 1) is attached to the drawbar slide I8. The

check valve I88 prevents the return of iluid from.

The upper portion of this valve chamber the sump I88 by (Figure 6) towhich one I88 is connected in any 'a,ess,eaa

pressure on the lower end of the plunger I88 to the cylinder I00, andhence hydraulically locks the drawbar slide I8 in itsrear position.Thus, in the position a of thevalve I88, the full pressure of the p mpIll is effective to force the piston I rearwardly and to swing the gangsinto their a when. the valve I08 is straightened position.

moved down to the position b, shown in dotted 3 lines in Figure 7, itwill be seen that fluid t is: the pump passes from the high pressureduct-18f into the chamber 'I8I andthence out of the latter through thepassage I82 and back to the sump I.

When the yoke 80 engages the front end ofthe channel section I8, thepiston I0! is prevented from being extended any farther, and thereforepressure builds up in the system, including the high pressure duct I39,the lower end of the passage or valve chamber I and the flexible tubeI88. Due to the fact that the yoke 80 may be' in any one of severalpositions of adjustment along the drawbar channel I5, t0 the rear. endof which the piston-I08 is connected, it willbe seen that the piston mayreach the end of'its permisis moved to its'neutral position b, 'a freepassage Y hold the same up in its dotted line position so long as thepump is running. Thus. wheneverths piston of thehydraulio unit 09 can:move outwardly no farther, the plunger I88 and associated parts serveas self-releasing means to relieve the pump of operating pressure,permitting it to idle while, at the same time, hydraulically locking thefluid in the cylinder I00. If desired,

there may be an adjustable restriction I80 in the passage I88. As longas the valve I08 remains in position a, thepump discharges idly through183,188, the restriction I88, I88 creating enough pressure to hold theplunger I88 up against a light spring. I81. When the'valve I58 is openedfrom the pump to thesump through the passages I8I and I82, and thespringI81 and/or gravity then returns the plunger I88 to its lowerpositiomclosing the by-pass I88, I88,

fluid below the plunger escaping to the sump through a leak passage I10.

sive movement at any one of several points within the cylinder I00 andthat, regardlessa's to which point may be reached when the. yoke comesl8, it is desirable to lock the fluid in the cylinder I00'in 'order'tohold the cylinder in its extended position, whether that is only apartially anism of the type which automatically releases itself upon theoccurrenceof excessive pressure within the high pressure side of thesystem.

The valve mechanism V shown in Figure '1 is of this type and representsany suitable valve mechanism of this character. Referring now moreparticularly to Figure 7, a bore or passage I10 communicates with thehigh pressure passage I89, the bore or'passage I10 communicaih ing witha relief valvechamber I18 in which a spring biased poppet release valveI1! is dis-' posed. At its upper end the relief valve chamber I18communicates with a bore or chamber I86 in which a by-pass controllingplunger I88 is slidably disposed in substantially leak-tight relation.At one side, the chamber I88 communicates with the high pressure ductI99 through a passage or duct I88, and at the other side, the chamberI86 communicates with the sump I89 through a passage I88, of slightlysmaller diameter than the passage I88. Whenever the piston I05 isprevented from extending any further and the pressure builds up .in thehigh pressure side of the system, as mentioned above, this pressure willopen the spring biased relief valve I12. This pressure, acting upon thelower end of the plunger I88, forces the latter upwardly untilcommunication is established between the by-pass ducts I83 and I88. Assoon as communication is established between the two passageways I "andup against the front end of the drawbar section When'it is desiredv torelease the fluid in the cylinder I00 and'perrnit it to-flow back to thesump I36, as is necessary when it is desired to permit the inner ends ofthe gangs to-drop back during forward travel of the outfit, the.controlling valve In is moved downwardly into its position 0, whichopens the check valve I00. In this position, fluid from the cylinder I08flows through a by-pass duct 280 past an'adjustable restriction 208 andaround the valve "I88 into the upper portion of the chamber or bore HIand from there thefluid from the cylinder I80 passes back to the sumpI88 under the control of the adjustment-208. Preferably, therestriction! is fairly free, and it maybe eliminated entirely, since aquick shift of the slings into their angled position is usually desired.

Any suitable means may be provided for controlling the valve I58.Preferably, however, the valve I58 is shifted into and out of itsseveral positions, by means of a hand lever indicated by the referencenumeral 2I0 inFigures 6 and '1.

The lever 2I0 is pivotally mounted on abracket "'"2II fixed to a portionof the valve casing I80 (Figure 6) and in'cludeaan arm connectedby alink III to the upper stem of the valve I98. I

In operation, when'it is desired tostraighten the gangs from anangledposition, the operator raises the valve handle 2I0, which causesfluid to flo'wunder pressure to the cylinder I80. This retracts thefront drawbar section relative to the rear drawbar section and thuspulls up on the inner'ends of the gangs. To angle the gangs from astraightened position, or to increase the angle when they are in anintermediate angled position, the operator momentarily, depresses the Ihand lever 2I0 of the valve mechanism V, which permits the oil to flowout of the cylinder I00 and hence permits the inner ends of the frontgangs to drop back, due to the pressure'of the soil againstathe innerends of the straightened gangs this pressure at the same time alsoserving ,toforce the oilback to the sump.

to force oil back intothe cylinder I00, not only aspects Of myinvention.

to aid in straightening the gangs under these conditions'but also tohold the gangs in their straightened position.

It will be seen from the foregoing description that I have providedpower-actuated means, energized by the power of the tractor, forrestoring the drawbar to its retracted position so that the gangs maybean'gled at any time by the pull of the forward draft without requiringthat the tractor or other propelling force be backed. The

power means which I have provided to this end may take two forms, onebeing spring means which is so constructed and arranged that power maybe stored and made available at any time for retracting the slidabledrawbar member. The second form incorporates a hydraulic cylinder andpiston or ram unit, including a source of pressure actuated by thetractor, arranged to shift the gangs into their straightened position bypower. The hydraulic ram units, is or No, may be considered either as apart of the disk harrow or as a part of the tractor. If the former, theimplement may be readily disconnected from the tractor. by releasing theclevis 49 and disconnecting the tube I at any suitable point, as at oneor the other of the connections I II or I", or at some pointparticularly designed to provide a ready disconnection. If the hydraulicunit is a part of the tractor, it may be readily disconnected from theimplement by removing the nut H4 and the screws I02. If desired, any

suitable form of quick disconnecting means may be used for attachingtheunit to the implement. Preferably, however, the unit is the part ofthe implement, since its range of action and capacity, as shown anddescribed above, has been designed to 'angle or straighten the harrow ina short;

period of time without excessive power requirements, and as explainedabove, controlling. valve mechanism of the self-releasing type is animportant part of the mechanism shown in Figures 5 to 7 for controllingthe disk harrow.

While I have shown and described above the may be employed in thepractice of the broader What I claim, therefore. by Letters Patent is:

a 1. A disk harrow comprising 'a" disk gang. frame means therefor, adrawbar slidable on said frame means, means detachably connecting thedrawbar with said gang .for shifting the latter by movement of saiddrawbar, and power means connected with said drawbar for shifting thedisk gang through movement of the drawbar when the gang is connected tosaid drawbar and shifting the latter independently of the gang when thegang is disconnected from the draw-,

' bar.

' 2. A- disk harrow comprising a disk gang, means with which said gangis shiftably connected, a drawbar shiftable with respect to said meansand adapted to be connected with the gang whereby draft force applied tothe drawbar is adapted to shift said gang, and spring means connectedwith said drawbar and said gang for shifting the drawbar when the harrow,is in transport position.

3. A'disk harrow comprising means serving as a frame, a pair of gangsmovably connected therewith for generally horizontal swinging anddesire' to secure preferred means in whlch'the principles of the presentinvention have been embodied, it late be understood that my invention isnot to be limited to the particular details shown and described above,but that, in fact, widely different means assaeos 7 serving as a frame,a pair of gangs movably connected therewith for generally horizontalswinging movement, a drawbar slidable relative to said frame means,draft links pivotally connected with said gangs, latch means optionallyconnecting said draft links with said slidable drawbar, fluid actuatingmeans connected between said frame means and the slidable drawbar forshifting the latter. relative to the frame means, and a source of fluidmeans under pressure on the tractor controllably connected with saidiluid actuated means.

5. A disk harrow as defined in claim 4, ther characterized by said meansbeing adapted to exert sufficient power to shift said gangs when saidlatch means is engaged with said slidable drawbar.

6. A disk narrow as defined in claim-4, further characterized by saidslidable drawbar being adapted to be connected to a tractor and saidlast mentioned means acting against said slidable drawbar for shiftingsaid harrow relative thereto when said latch means releases said linksfrom connection with the slidable drawbar.

7. In a disk harrow, frame means, a pair of disk gangs pivoted at their,inner ends to said frame means for generally horizontal swingingmovement, a drawbar comprising two relatively slidable members, oneconnected with said frame means and the other slidably generally foreand aft relative to said one drawbar member, a front slide adapted to bereleasably latched to said slidable drawbar member, draft linksconnecting said front slide with the outer ends of saidv gangs, andmeans connected between said frame means and the inner end of saidslidable drawbar member and adapted to retract the latter.

- 8. A disk harrow as defined in claim 7, fur-f ther characterized bysaid retracting means ccmp s s a spring.

' 9. A disk harrow as defined in claim '7, furether characterized bysaid slidable drawbar memv her being adapted to be attached to a tractorand said retracting means comprising a hydraulic power unit derivingpower from said tractor.

10. In a disk harrow, a pair of gangs, a draw 1 between said othermember and the outer ends v of said gangs, and means connected with saidI members for shifting them into telescoped relation.

11. In atraetor-propelled disk harrow, a drawbar construction comprisinga first member, a

' second member slidable with respect to the forward portion of saidfirst member, means deriving operating energy from said tractor andconnected between said first member and the rear end of said secondmember for moving the latter relative to said first member, a pair ofgangs pivotally connected at their inner ends with the rear end of saidfirst member, a slide on the forward portion of said second member andconnected with the outer ends of said gangs, and means limiting themovement of said slide relative to said second member.

12. In a disk harrow, a drawbar construction comprising a first memberadapted to be connected with the disk harrow, a second member slidablewithin said first member, and a spring connected at one end to the diskharrow end of said first member and to the other member adjacent theopposite end thereof.

13. In a disk harrow, a drawbar construction comprising a first memberconnected at one end with said harrow, a second member slidable withinthe other end of said first member and having at its other end draftreceiving means, spring means connected at one end to said one end ofthe first drawbar member and at its other end with the draft receivingend of said second drawbar member, draft applied to the latter servingto extend said drawbar members and pair of disk gangs pivotallyconnected at their.- inner ends with said frame means for generallyhorizontal swinging movement, a drawbar construction comprising a rearmember connected at its rear end with said frame means and a. slidabledraft receiving member telescopically associated with and extendingforwardly of said rear member, draft connections adapted to bereleasably latched with said forwardly extend ing draft member andconnected with the outer ends of said gangs, whereby when said draftreceiving member is in retracted position relative to said rear draftmember and said draft connections are latched to said draft receivingmember, draft applied to the latter with said connections latchedthereto will act through the latter to angle said gangs to an extentdepending upon the position said draft connections are latched to saiddraft receiving member, means acting between the rear member and theslidable fdraft receiving member of said drawbar construction forretracting said draft ,receiving member rearwardly relative to said reardraft member, and stop means carried by said draft receiving member andengageable with said draft connections for limiting the amount saiddraft. receiving member may be retracted by said re- A tracting means,said stop means serving to de- 1 termine an angled position for saidgangs when draft applied to said draft receiving member acts throughsaid draft connections for pulling the outer ends of said gangsforwardly.- 4

15. A disk harrow comprising frame means, a pair of disk gangs pivotedat their inner ends to said frame means andswingable generallyhorizontally, a sliding drawbar movable generally longitudinallyrelative to said frame means, a slide embracing said slidable drawbarand linkconnected to the outer ends of said gangs,.latch means carriedby said slide for controlled engagement with said sliding drawbar,forward movement of said sliding drawbar from its retracted positionrelative to said frame means when said slide is latched to'the outerportion of said sliding drawbar serving to angle said gangs andreleasing said latch means permitting said slide to move rearwardlyalong the sliding drawbar and the gangs to move into their straightenedposition, retracting meanson the harrow for moving said drawbarrearwardly relative to said frame means and adjustable stop meanscarried at the forward portion of said sliding drawbar and serving tolimit the rearward movement thereof by said retracting means when saidlatch means is released. I

16. A disk harrow comprising frame means, a pair of disk gangs pivotedat their inner ends to said frame means for generally horizontalswinging, a drawbar slidably disposed relative to said frame means andadapted to receive draft from a propelling means, connections betweenthe outer ends of said gangs and said slidable drawbar, said connectionsbeing adapted to be latched to said slidable drawbar when the latter isin its retracted position relative to said frame means, whereby theapplication of draft to said drawbar serves to extend the latter and atthe same time angles saidgangs through said draft connections, saiddraft connections being go releasable from said drawbar so that the soilresistance acts to swing said gangs into their straightened position andto move. said draft connections rearwardly along said drawbar, andratchet latch means for connectingsaid draft connections with saiddrawbar to provide for shifting the same into its retracted positionwithout releasing the, latch means, whereby a subsequent forwardmovement of said drawbar relative to said frame-means acts through saidso draft connections to angle said gangs.

- 1'1. A disk harrow comprising frame means, a

" pair of disk gangs pivoted at their inner ends to said frame means forgenerally horizontal swinging, a drawbar slidably disposed relative tosaid frame'means and adapted to receive draft from a propelling means,connections between the outer ends of said gangs andsaid'slidabledrawbar, said connectionsbeing adapted-tome latched to said slidabledrawbar when the latter is in its retracted position relative to saidframe means, whereby the application of draftto said drawbar serves toextend the latter and at the same time angles said gangs through saiddraft -,connections, said draft connections being releasable from saiddrawbar so that the soil resistance acts .to swing said gangs into theirstraightened position -andto move said draft Aconnections rearwardlyalong said drawbar, ratchet latc'h'means for connecting said draft5.eonnections with said drawbar to provide for ..shifting the same intoits retracted position without releasing the latch means, whereby asubsequent forward movement of said drawbar relative to said, framemeans acts through said draft connections to angle said gangs, and meansacting between said frame means and said drawbar for shifting the latterinto its retracted position.

18. A disk harrow comprising frame means, a pair of disk gangs pivotedat their inner ends to said frame means for generally horizontalswinging, a drawbar slidably disposed relative to said frame means andadapted to receive draft from a propelling means, connections betweenthe outer ends of said gangs and said slidable drawbar, said connectionsbeing adapted to be latched to said slidable drawbar when the latter isin "its 4 rearwardly along said drawbar, and a hydraulic power drivencylinder and piston unit connected at one end with said frame means andat the other end with said drawbar for moving the latter into itsretracted position.

19. A disk harrow comprising frame means, a harrow gang shiftablerelative thereto, a drawbar slidable relative to said frame means, meansacting between said frame means and said drawbar for shifting onerelative to the other, and means connected between said slidable drawbarand the gangs for shifting the latter by virtue of movement of thedrawbar relative to said frame means.

20. An agricultural implement adapted to be propelled by a tractor andcomprising a disk narrow including means serving as a frame, a pair ofdisk gangs having their inner ends connected with said frame means, adraft receiving member adapted to be moved relative to said frame means,said draft receiving member being adapted to be connected to saidtractor, optionally releasable connections between said member and theouter ends of said gangs whereby, when said member is in one positionrelative to said frame means; draft force applied to said member may beutilized for angling said gangs, and means on the harrow deriving powerfrom the tractor for moving said draft receiving member into saidposition.

21. A disk harrow comprising frame means, a draft receiving membermovable relative to said frame means, a pair of gangs, optionallyactuatable connections between said draft receiving member and outerends of said gangs whereby when said draft receiving member is in oneposition relative to said frame means, a forward pull on said draftmember acts to angle said gangs, and means acting between said framemeans and said draft receivingmember for moving the latter into said oneposition.

22. In a harrow, the combination of a harrow device, means providing formovement thereof to different operating positions, adjustable means forlimiting the movement of the harrow device in one direction so as toprovide for setting the harrow device into any one of said operatingpositions, and power means separate from said limiting means for movingsaid harrow device toward its non-operating position irrespective of theparticular position in which the harrow device has been operating.

23. In a harrow, the combination of a harrow device, means providing formovement thereof to different operating positions, means for setting theharrow device into any one of its several operating positions, and powermeans acting through said setting means for moving the gangs from anyworking position into their transport position, said power meansincluding pressure responsive self-releasing mechanism adapted to bereleased when the gangs. reach their transport position.

24. A tractor disk harrow comprising a draft frame, a pair of gangsswingable generally horizontally relative thereto from an angledposition into a straightened transport position, the pressure 01' thesoil tending to swing said gangs beyond their transport position, meansto adjust the degree of angle of the gangs in the working positionthereof, means to prevent the gangs from moving out of a workingposition beyond their transport position, and hydraulic power meansenergized by the power of the tractor for shifting the gangs to atransport position from any angled working position, said hydraulicpower means having a range of movement sumcient to move the gangs fromtheir extreme angled position to theirtransport position and arranged tobe disabled when said gangs are moved to their transport position fromany intermediate angled position.

25. In a harrow, the combination of a harrow device movable differentdistances into and out of any one of a series of angled operatingpositions, pressure actuated means adapted and having the capacity toshift said device through the maximum distance required to move the samefrom one position to another, means for terminating the movement of saiddevice at one of said positionsirrespective of the distance throughwhich the device was shifted in reaching said position, andself-releasing valve mechanism controlling the application of pressureto said pressure actuated means and responsive to an increase in thepressure in the latter, resulting from termination of movement by saidterminating means, for diverting pressure from said pressure actuatedmeans.

26. A disk harrow adapted to be propelled by a tractor. comprising thecombination of one or more swingable disk gangs. a drawbar having stopmeans adjacent each end thereof, one of said stop means determining thestraightened transport position of the gangs and the other of' said stopmeans being adjustable relative to the first stop means and operable todetermine the angled position of the gangs, and self-releasing gangshifting mechanism adapted to derive power from the tractor andoperative through a given range of movement sufficient to shift thegangs the maximum distance from one stop means to the other, saidshifting mechanism automatically releasing when the gangs are movedagainst one of said stop means through a distance less than said givenrange of 'maximum movement.

27. .The combination of a disk barrow having a gang'adapted to be swunginto and out of angled position, means limiting movement of I said gangand adjustable means for determining the degree of angle of said gangs,and fluid pressure actuated means adapted to move said gang variousdistances between any one of a plurality of angled working positions anda non-working position, a source of fluid under I pressure, andcontrolling valve mechanism connected between said pressure source andsaid pressure actuated means and including means responsiveto a pressureincrease in said pressure actuated means for automatically releasing thepressure exerted against said fluid actuated device when said gangreaches one of its end positions as defined by said limiting means.

28. The combination of a disk harrow having a disk gang adapted to beshifted various distances between any one of a series of adjustedpositions and a substantially fixed position, two limit meansdetermining the end positions, respectively, of said tool means,pressure actuated means operably connected with said tool means andadapted to shift said tool means through the maximum distance from oneposition to another, a. source of pressure, and self-releasing valvemechanism controlling the application of pressure to said pressureactuated means and responsive to an increase in the pressure in thelatter, resulting from termination of movement of said tool means bysaid limit means, for

hydraulic means connected I by a tractor, frame means, a

diverting pressure from said pressure actuated means.

29. The combination of a tractor, a disk harrow having frame means, adisk gang swingably connected therewith for movement between an adjustedangled position and a straightened position, and limit means, includingan adjustable part, defining said positions. a single action ramincluding a plunger and cylinder, one anchored to said frame means andthe other connected with said gang to shift the same through variousdistances into one of said positions, a source of pressure on thetractor, and controlling, valve mechanism between said source and saidram and including a main valve. a by-pass around said main valve, avalve controlling said by-pass, and means responsive to the increase ofpressure in said cylinder, after said gang is moved into one of itspositions and said limit means prevents further movement of said gangand thereby prevents further relative movement between said plunger andcylinder, for opening said by-pass valve.

30. A disk harrow comprising a pair of disk gangs, drawbar meanspivotally connected with the inner ends'of said gangs, a member movablealong said drawbar means and operatively connected with the outer endsof said gangs, and

between said drawbar means and said member for shifting said 31. In adiskharrow, frame means, a pair of disk gangs pivoted at their innerends to said frame means for generally horizontal swinging movement, tworelatively slidable members, one connected with said frame means and theother slidable generally fore and aft relative to said one member, draftlinks connectingsaid slidable member with the outer ends of said gangs,and a hydraulic unit including a cylinder connected with one of saidmembers and 'a piston consaid slidable member relative to the othermember when the slidable member is disconnected from said draft links.

34. In a disk harrow adapted to be propelled by a tractor, frame means,a pair of disk gangs pivoted at their inner ends to said frame means forgenerally horizontal swinging movement between angled and straightenedpositions, two relatively slidable members, one connected with saidframe means and the other slidable generally fore and aft relative tosaid one member, draft links connecting said slidable member with theouter ends of said gangs, and a hydraulic unit deriving power from thetractor and including a cylinder connected with one of said members anda piston connected with the other member for shifting said slidablemember and swinging said gangs about their points of pivot connectionwith said frame means into their straightened position.

35. A tractor harrow comprising frame means, a disk gang pivoted theretofor horizontal swinging movement, a drawbar slidably mounted on saidframe means and adapted to be connected at its forward end with thetractor, a connection between said drawbar and said gang whereby forwardmovement of the drawbar relative to said frame means by the forwardmovement of the tractor shifts said gang into one position, andpower-actuated means acting between said frame means and said slidabledrawbar and reacting through the latter against the tractor for shiftingthe frame means and gang generally forwardly relative to the drawbar.

36. A disk harrow adapted to be connected with a propelling force andcomprising a pair of gangs swingable between angled and straightenedpositions, two-part drawbar means, one part of which is connected withthe inner ends of said gangs and the other part of which is shiftablerelative to said one part and is connected with the outer ends of thegangs, said other part being the part nected with the other member forshifting said slidable member and swinging said their points of pivotconnection with said frame means.

32. In a by a tractor, pivoted at their inner ends to said frame meansfor generally horizontal swinging movement, two

diskharrow adapted to be propelled relatively slidable members, oneconnected with said frame means and the other slidable generally foreand aft relative to said one member, draft links for connecting saidslidable member with the outer ends of said gangs, means deriv ingenergy from the tractor and connected between and supported on at leastone of said members for shifting said slidable member relative to theother member, and means serving as an adjustable stop on said one memberand positioned to be engaged by the slidable member for variablylimiting the movement of said sliding member relative to said othermember by the action of said shifting means.

33. In a disk harrow adapted to be propelled pair of disk gangs pivotedat their inner ends to said frame means for generally horizontalswinging movement, two relatively slidable members, one connected withsaid frame means and the other slidable generally fore and aft relativeto said one member, draft links connected with the outer ends of saidgangs, releasable means for connecting the draft links with saidslidable member, and spring means energized by the power of the tractorand connected between said members for shifting frame means, apair ofdisk gangs gangs about that receives the propelling force, and poweractuated means for retracting said parts to swing the gang from anangled position into straightened connected at its inner position.

means,

tra'ctor disk harrow comprising frame a gang'of earth working diskssuitably I end with said frame means and movable relative thereto intoand out of angled and non-working positions, a single acting hydraulicunit deriving operating energy from the tractor and connected with saidgang for swinging its outer end rearwardly into one position, valvemeans for releasing the pressure in said unit to provide for swingingthe gang into its other position, and means operative when the pressurein said unit has been released whereby soil resistance against the innerend of said gang swings the latter into said other position.

38. A disk harrow adapted to be propelled by a tractor, comprising framemeans, a pair of disk gangs pivotally connected with said frame meansfor swinging movement between angled and straightened positions, draftreceiving means slidably connected with said frame means, meansconnecting the movable ends of the gan s with said draft receivingmeans, whereby rearward movement of saidslidable draft receiving meansrelative to the frame means moves the gangs into a straightened positionwhen the draft receiving means is connected with the movable ends of thegangs, said connecting means being releasable, means deriving power fromthe tractor operatively connected with the frame means and the gangs formoving said gangs toward one position by power, and means wherebyforward movement transmitted to the harrow through said draft receivingmeans will straighten said gangs when the latter are disconnected fromthe slidable draft receiving means.

39. A disk harrow adapted to be propelled by a tractor, comprising framemeans, a pair of disk gangs pivotally connected with said frame meansfor swinging movement between angled and straightened position anddisposed whereby pressure of the soil against the disks tends to swingthe gangs from one position to another, draft receiving means slidablyconnected with said frame means, and means deriving power from thetractor operatively connected between said slidable means and said framemeans so as to react against said slidable means for moving said gangsinto said one position, said power means including a hydraulic ram unitand means for hydraulically locking the ram unit in extended positionwhen said gangs are moved into said one position, so as to preventmovement of said gangs out of said position.

40. A disk harrow adapted to be propelled by a tractor, comprising framemeans, a pair of disk gangs pivotally connected with said frame meansfor swinging movement between angled and straightened positions, draftreceiving mean movably connected with said frame 'means, a part movablerelative to said movable draft receiving means and connected with saidgangs, means deriving power from the tractor operatively connectedbetween said part and said frame means so as to react against said partfor moving said angs into one position, and means for operativelyconnecting said part with said movable draft receiving means wherebymovement of the latter swings said gangs.

41. A disk harrow comprising a pair of disk gangs, a drawbarconstruction comprising a pair of slidably associated members, meansconnecting one of said member -with the inner ends of said gangs, a partslidable on the other of said members, means connecting said part withthe outer ends of said gangs, and means -;pro'vid ing a one-- wayconnection between said part andsaid other member, whereby movement ofsaid other-mem her in one direction moves said peri e tli'e'outer endsof said gangs, said other member-being movable freely relative to saidpart without moving the outer ends of said gangs.

42. A disk harrow comprising a disk gang, 8. drawbar constructioncomprising a pair of slidably associated members, mean connecting one ofsaid members with one end of said gang, a part slidably associated withthe other of said memhere, means connecting said part with the other endof said gang, and one-way connection means connecting said part withsaid other member,

whereby movement of the latter relative to said 2.

one member in one direction serves to shift the position of said gangbut movement of said other memberin the other direction does not shiftsaid gang.

43. A disk harrow comprising frame means, a pair of disk gangs pivotedat their inner ends to said frame means for generally horizontalwinging, a drawbar slidably disposed relative to said frame means andadapted to receive draft from a propelling means, one-way ratchet latchmeans connecting the outer ends of said gangs with said slidabledrawbar, said one-way latch means being adapted to be latched to saidslidable drawbar when the latter is in its retracted position relativeto said frame means, whereby the application of draft to said drawbarserves to extend the latter and at the same time angle said gangsthrough said one-way latch means, the latter providing for shifting thedrawbar into its retracted position without releasing the one-way latchmeans, and means for retracting said drawbar.

44. A disk harrow comprising frame means, a disk gang movably connectedtherewith, a drawbar movable relative to said frame means, a slidedisposed on said drawbar and connected with said gang, power meansanchored to said frame means and operatively connected with said gangthrough said slide for shifting the gang in one direction by power, andmeans for causing movement of said drawbar relative to said frame meansto shift said gang in the other direction.

45. A tractor disk harrow comprising a pair of disk gangs, frame meanswith which the inner ends of the gangs are connected, a member shiftablewith respect to said frame means and adapted to be connected with saidtractor to receive draft therefrom, means releasably connecting theouter ends of said gangs with said shiftable member, and power meansreacting against said frame means and said shiftable member for forcingsaid gangs from an angled position into straightened position.

46. A tractor disk harrow comprising a pair of disk gangs, frame meanswith which th inner ends of the gangs are connected; a member shiftablewith respect to said frame means and adapted to be connected with saidtractor to receive draft therefrom, means releasably connecting theouter ends of said gangs with said shiftable memher, and power meansreacting against said frame means and said shiftable member for forcingsaid gangs from an angled position into straightened position, saidgangs also tending to move from their angled position into theirstraightened position by releasing said releasable connecting means.

47. A tractor disk harrow comprising a pair of disk gangs, frame meanswith which the inner ends of the gangs are connected, a member shiftablewith respect to said frame mean and adapted to, be connected with saidtractor to receive draft therefrom. means releasably connecting theouter ends of said gangs with said shiftable memher, and power meansreacting against said frame means and said shiftable member for forcingsaid gangs from an angled position into straightened position, saidgangs also being straightened by backing the tractor while saidreleasabl connecting means connects the gangs with the shiftable member.

48. A tractor disk harrow comprising a pair of disk gangs, frame meanswith which the inner ends of are connected, a member shiftable withrespect to said frame means and adapted to be connected with saidtractor to receive draft therefrom, power means acting against saidframe means 'and' the outer ends of the gangs for forcing the latterinto one position, and means connecting said shiftable member with saidgangs whereby backing of the tractor acts through the shiftable memberfor also forcing the gangs into a straightened position. 49. A tractordisk harrow comprising a pair 6 disk gangs, frame means with which theinner' ends of the gangs are connected, a member shiftable with respectto said frame means and'adapted to be connected with the outer ends ofthe gangs, means for causing the backing of the tractor to shift saidshiftable member rearwardly relative to said frame means and therebyforce the gangs into straightened position, and power means actingagainst said frame means for shifting said angs while the tractor actsthrough said frame means to propel the harrow forwardly.

50. A tractor disk harrow comprising a pair of disk gangs, frame meanswith which the inner ends of the gangs are connected, a member shiftable with respect to said frame means and adapted

